What can be concluded about Benedick's character based on the gulling scenes and the contrast in his attitudes before and after he was tricked into falling in love with Beatrice?

When the play begins, Benedick and Beatrice are already in love, but both of them are too proud to admit that they love one another. Benedick hides his feelings by pretending to be a ladies' man who has no interest in a committed relationship.
The gulling scenes establish that their friends know that the only way they will ever admit to their feelings is if they know that their feelings will be reciprocated. In Benedick's gulling scene, he hears that Beatrice is distraught because of her love for him and declares that he will love her back because it is the gentlemanly thing to do. Really, the audience knows that Benedick has been in love with Beatrice all this while and only needed an excuse to act on his feelings.
After the gulling scene, Benedick does a 180 by dropping the hyper-masculine swagger and immediately seeking a committed relationship with Beatrice. From this, we may deduce that the Benedick we met at the beginning of the play was only another mask to conceal the true Benedick, who loves Beatrice and would do anything for her.